My intention in preparing this article is to bring to the knowledge of the community involved in the production of pigs, which based on a research program conducted with pigs of different sexes, which is feasible and advantageous for the producer, to explore the earning capacity compensatory weight of pigs, in the growth and finishing phases I and II.
The experiments to which we refer were conducted with castrated male pigs, immunocastrated males and females, selected at the end of the daycare phase, aged approximately 63 days.
The animals were distributed into 4 treatments, which corresponded to sequences of 3 levels of lysine. digestible (LD), with a reduction of 0.10% of LD per period, which lasted, respectively, 40, 30 and 30 days, thus totaling 100 days of experiment. Among the 4 treatments, LD levels were also decreased by 0.10%. The animals were weighed at the end of each period.
In all experiments, the first sequence of LD corresponded to the requirement of the animals, and in the others, the levels of lysine were gradually decreased by 0.10%, therefore with lower contributions of LD. For example, if the animal's LD requirement in the first 40-day period, which normally corresponds to the growth phase, was 1.10% LD, in the remaining 2 periods it would correspond to 1.00% and 0.90% LD . Thus, T1 would correspond to the 1.10% sequence; 1.00% and 0.90 LD. E. among the treatments, the LD sequences were also reduced by 0.10%, with T2 corresponding to 1.00%, 0.90% and 0.80%; T3 at 0.90%; 0.80% and 0.70% and T4 at 0.80%; 0.70% and 0.60%.
In all experiments, without exception, when the first 40-day period was evaluated, the animals that received the highest LD level (1.10%), which corresponded to their requirement, showed the best performance. However, when the evaluation was carried out at the end of the 100-day experimental period, with the animals aged approximately 163 days, there was no difference in performance and in the amount of meat in the carcass of the animals between the 4 treatments. T1 and T4, even at the 0.80% LD level of T4, resulting in worse performance of the animals in the first 40-day period. What studies have shown is that, in regions where animals are slaughtered weighing 100 kg or more, it is feasible to use nutrition programs using LD levels significantly lower than the requirements of animals, in this case T4, even animals having presented the best performance at the level of 1.10% LD, in this case T1, in the first 40 days of the experiment.
The question that remains is, why is this possible? It can be deduced based on these results, that the pigs presented compensatory weight gain and that this practice of nutrition is viable as long as the animals are slaughtered weighing over 100 kg. This is because it is known that the maximum deposition of protein in the carcass of pigs occurs around 65 to 80 kg, variation justified by the genetics of the animals, the higher weight for the use of this nutrition program, would then be of fundamental importance to allow the animals enough time to recover the performance and quantity of meat deposited in the carcass, equaling that of the animals that performed better with the highest LD level, in the first period. In all experiments, all animals were slaughtered in commercial refrigerators and their carcasses were evaluated. Another important detail to be highlighted is that, in addition to maintaining the final performance and quantity of meat in the carcass, the supply of diets with lower levels of LD, resulted in an improvement in the quality of the meat of the animals, due to the increase in the percentage of meat. intramuscular fat, which was evaluated in one of the experiments. In the available literature, there are studies that prove that the supply of diets with lower levels of LD results in an improvement in the quality of the meat of pigs, by increasing the concentration of intramuscular fat. It should also be considered that the use of this nutrition program, in addition to reducing the cost of production, also contributes to the environment, significantly reducing the pollutant load of waste. Finally, we inform you that the experiments, to which we refer, are published in ENGORMIX.